Add workspaces, conversation sessions, app-managed computers and pictures

- Rail: Add icon with stacked form modals (bot, workspace, computer),
  coordinator, recent bots with "See all bots", Workspaces section, and
  a workspace mode listing only its crew
- Workspaces: page for context, bots (per-workspace instructions and
  memory), computers (default, link, unlink), models and delete;
  conversations scoped per bot per workspace
- Sessions: conversations split into searchable, reopenable sessions
  with carry-over summaries; sessions and new-session header icons
- Computers: created and provisioned over the docker socket, home dir
  kept at DATA_DIR/computers/<id> after delete; super admins only
- Models: workspace settings win over a bot's own, then the defaults
- Pictures for bots and workspaces; bots editable from the header
- Coordinator tools: update_workspace, set_bot_workspace_instructions

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/layouts/bots/(partials)/rail-add-button.tsx

@@ -0,0 +1,26 @@
+import { useContext } from "react";
+import Button from "@moduletrace/twui/layout/Button";
+import { Plus } from "lucide-react";
+import { AddFlowContext } from "../(data)/add-flow-context";
+
+/**
+ * The rail header's Add icon: opens the Add modal (a bot, a workspace or a
+ * computer).
+ */
+export default function RailAddButton() {
+    const { openAdd } = useContext(AddFlowContext);
+
+    return (
+        <Button
+            title="Add a bot, workspace or computer"
+            aria-label="Add a bot, workspace or computer"
+            type="button"
+            variant="ghost"
+            color="text"
+            onClick={openAdd}
+            className="hidden lg:flex shrink-0 p-1.5! rounded-default-sm text-ink-secondary dark:text-ink-secondary hover:text-ink hover:dark:text-ink hover:bg-sunken hover:dark:bg-sunken transition-colors duration-[var(--m-fast)] focus-visible:ring-2 focus-visible:ring-ink"
+        >
+            <Plus size={18} aria-hidden />
+        </Button>
+    );
+}